Thousands of adult men suffer from sexual abuse, a survey has discovered.

Researchers from three London hospitals interviewed 2,474 men and found that around three per cent had experienced sexual abuse as adults.

Of the 71 men who reported non-consensual sex experiences, one in five had been raped by a man.

The researchers found a higher rate of abuse among younger men - indicating that the problem is on the increase.

Men who had suffered sexual abuse were more likely to suffer from psychological problems than the general population, including alcohol misuse and self-harm.

But the overwhelming majority decided to suffer in silence, failing to seek professional help or report the matter to the police.

Most extensive study yet

The researchers are the first to carry out such an extensive study into sexual abuse among men.

They warn that medical professionals need to be aware that these men are psychologically vulnerable.

Writing in the British Medical Journal, they warn that their estimate of the prevalence of sexual abuse in men is likely to be a conservative one as many victims do not wish to discuss what has happened to them.

While interviewing the men, the researchers also found that more than one in 20 (5.4%) had been subjected to non-consensual sexual experiences as children, and that abuse as a child was often followed by a similar experience in adulthood.

The researchers point out that previous studies have concentrated on the possibility of sexually abused boys becoming perpetrators in adulthood.

The possibility of early abuse leading to further victimisation as adults is a concept that has been neglected, they say.

Majority are heterosexual

Overall the study found that of the men who said they had sex forced on them, 46% said it was by a woman.

Of those men who reported non-consensual sexual experiences with other men, most defined themselves as primarily heterosexual.

However, men who had consensual sex with other men were six times more likely to have non-consensual sex as an adult.

The researchers point to research that shows that, on average, gay and bisexual men have more sexual partners than heterosexual men.

The speculate that increasing numbers and anonymity of sexual partners may increase the risk of non-consensual sex.

One of the authors, Professor Michael King, of the Royal Free and University College Medical School, said only 1% of men who had suffered sexual abuse reported it to the police.

He said it was less clear how many sought medical support as they might seek help for the subsequent psychological difficulties, rather than the abuse itself.

He said: "The public need much more information on the problem so that men are less reluctant to report to professionals and to the police.

"For many men these problems stem from childhood experiences but, if the cause remains unknown, the problems are difficult to solve.

"Doctors and other professionals need to be aware that this occurs and that men with psychological problems may have this as part of their history - just as is recognised for women."

Official police figures show that 227 men were raped in 1995, an increase of 51% from 1994 figures.